Direct detection of chicken genomic DNA for gender determination by thymine-DNA glycosylase.

1. Birds, especially nestlings, are generally difficult to sex by morphology and early detection of chick gender in ovo in the hatchery would facilitate removal of unwanted chicks and diminish welfare objections regarding culling after hatch. 2. We describe a method to determine chicken gender without the need for PCR via use of Thymine-DNA Glycosylase (TDG). TDG restores thymine (T)/guanine (G) mismatches to cytosine (C)/G. We show here, that like DNA Polymerase, TDG can recognise, bind and function on a primer hybridised to chicken genomic DNA. 3. The primer contained a T to mismatch a G in a chicken genomic template and the T/G was cleaved with high fidelity by TDG. Thus, the chicken genomic DNA can be identified without PCR amplification via direct and linear detection. Sensitivity was increased using gender specific sequences from the chicken genome. 4. Currently, these are laboratory results, but we anticipate that further development will allow this method to be used in non-laboratory settings, where PCR cannot be employed.

Intra-uterine Infection with Babesia bovis in a 2-day-old Calf.

Infection with Babesia bovis was diagnosed in a 2-day-old female calf apparently transmitted in utero. The calf was born as the second calving to a cross-bred beef cow permanently on pasture. Diagnosis was based upon identification of B. bovis in peripheral blood smears and clinical signs which included fever, jaundice, pale mucous membranes and convulsions. Anaemia, leucocytosis, thrombocytopenia and lymphocytosis were noted at the febrile acute stage of the disease. The blood smears revealed evidence of regeneration of toxic neutrophils with a left shift, severe spherocytosis and high degree of basophilic stippling. Elevated concentration of aspartate aminotransferase, lactate dehydrogenase, and creatine kinase were also noted, and were probably the result of haemolysis, dehydration and muscle damage because of recumbancy. Elevated total bilirubin concentration following haemolysis resulted in jaundice. The neurological symptoms observed were probably caused by sludging of parasitized erythrocytes in the brain capillaries. The calf recovered following treatment with diminazene aceturate and the recovery was followed up clinically, haematologically and biochemically.

Keratoconjunctivitis and periorbital papillomatosis associated with heavy periorbital infestation by the tail louse Haematopinus quadripertusus in heifers.

Heifers (Israeli-Holstein), aged 12-18 months, permanently maintained in open barns on an inadequate nutritional regime were found to be moderately to heavily infested by Haematopinus quadripertusus, the tail louse. The severely infested heifers showed keratoconjunctivitis and periorbital papillomatosis. Two treatments with an alpha-cypermethrin pour-on product 14 days apart controlled the lice, and were followed by alleviation of the inflammation and regression of the papillomas.

The effect of the ovine host parasitaemia on the development of Babesia ovis (Babes, 1892) in the tick Rhipicephalus bursa (Canestrini and Fanzago, 1877).

Batches of Rhipicephalus bursa adult ticks were fed on two lambs with 10.0% (batch 1) and 0.3% (batch 2) Babesia ovis parasitaemia, respectively. Haemolymph and eggs were checked for parasites daily after detachment, before and after appearance of B. ovis in the lamb's blood.B. ovis kinetes were found in the haemolymph and eggs earlier in the engorged ticks detached before appearance of the parasite in the host blood. Rates of haemolymph and egg infection with B. ovis as well as the percentage of infected eggs were much higher in batch 1 (10% lamb parasitaemia) than in batch 2 ticks (0.3% lamb parasitaemia). In eggs incubated at 28 degrees C the optimal period to look for kinetes seems to be days 4-9. Heavily infected ticks laid fewer less eggs within a shorter oviposition period. Pre-oviposition, pre-hatching periods and egg hatchability were not affected. Various parasitic forms are described in the haemolymph and the eggs.

The life cycle of Rhipicephalus bursa Canestrini and Fanzago, 1877 (Acarina: ixodidae) under laboratory conditions.

The biology of Rhipicephalus bursa has not been thoroughly studied. In the present study R. bursa was bred in the laboratory and its biology worked out.Larvae, nymphs and adult Rhipicephalus bursa ticks were fed on sheep and were held at 28+/-1 degrees C and 89+/-1% relative humidity (RH) in a darkened incubator. The average weight of engorged females was 0.676g (range 0.353-1.128). The average weight of eggs laid by females was 0.344g (range 0.146-0. 554g). The average number of eggs laid was 7527 (range 6263-8860) and this was significantly correlated with the weight of the females. The index of Reproduction Efficiency (number of eggs per g weight of female) was 8469.6. The index of Conversion Efficiency (weight of eggs per weight of female) was 0.5037. Peak daily oviposition, at an average of 840 eggs per female, occurred on the 6th day of oviposition. After Day 6, the rate declined steadily. The average duration of the preoviposition period was 5.1 days (range 4-7 days). The oviposition period averaged 16.5 days (range 12-21 days), and was significantly related to both the weight of the female and the number of eggs laid. The average pre-hatching period was 31.2 days (range 24-45 days). The average feeding time of larvae and nymphs of this two host tick was 15.2 days (range 14-18 days). Female ticks fed for 5.9 days on the average. Heavier nymphs produced females and a shorter premoult period was noted for lighter male nymphs. The males/females ratio was 1.38:1. The time taken to complete the life cycle was on average 142.45 days (range 99-254 days).

Arthropod parasites of Nubian ibexes (Capra ibex nubiana) and gazelles (Gazella gazella) in Israel.

In a 20-year survey the following ectoparasites were collected from Nubian ibexes: larvae of an unidentified Oestrus sp. collected from the nasal cavities, sinuses and horns, hippoboscid flies (Lipoptena chalcomelaena) specific to the Nubian ibex, blood sucking lice (Linognathus africanus) and unidentified biting lice (Damalinia sp.). Ibexes were severely infested with the cattle tick, Boophilus annulatus; a few Hyalomma anatolicum excavatum ticks were also collected. In five ibexes kept in two zoos, showing otitis, Psoroptes cuniculi, was identified, and from skin scrpaings of nine animals with severe dermatitis in three other zoos, Sarcoptes scabiei was isolated. Infestation of Nubian ibexes with sucking and biting lice as well as H. anatolicum excavatum is reported for the first time. The ectoparasites collected from gazelles were: hippoboscid flies (Lipoptena capreoli), calliphorid flies (Lucilia sericata and Calliphora sp.), sucking lice (Linognathus africanus and Solenopotes capillatus) and unidentified biting lice (Damalinia sp.), fleas (Ctenocephalides felis felis), and ticks, B. annulatus, Rhipicepahlus bursa, Rhipicephalus turanicus, H. anatolicum excavatum and H. marginatum rufipes. In skin scrapings of four gazelles with local dermatitis in the fetlocks Chorioptes bovis was identified. Neoschoengastia sp. was found in craters between the claws in three gazelles.

Chorioptic mange (Acarina: Psoroptidae) in domestic and wild ruminants in Israel.

In a 20-year-survey, 9364 dairy cattle in 324 herds kept under a zero-grazing management, 1252 beef cattle in 46 herds grazing all the year round, 3347 sheep in 134 herds (only 26 are grazing herds), and 872 goats in 47 herds (only 20 are grazing) were examined. The mites collected from cattle were identified as Chorioptes texanus only, and those from sheep, goats and gazelles were identified as C. bovis. Chorioptic mange was not diagnozed in grazing beef cattle, ibexes and housed animals (as compared to grazing herds), and in rams and billy goats. Holstein-Israeli bulls kept in insemination centres were not clinically infested, whereas four Charolais bulls were infested with chorioptic mange. Infestation rate was higher in older animals than in younger ones. Hoggets and young goats over 10 months and heifers over 13 months were found clinically infested with Choriopic mites. Lesions were not usually extensive and occurred mainly in predilection sites. The ocular form in sheep and the groin form in goats are very uncommon and apparently are reported for the first time. Chorioptic mange was recorded generally throughout the year. In our study seasonal distribution could not be demonstrated in cattle, while in sheep and goats the highest infestation rate occurred in February to March and the lowest in August and September.

Clinical, clinico-pathological and serological studies of Babesia ovis in experimentally infected sheep.

Clinical, clinico-pathological and serological studies were performed in sheep experimentally infected with Babesia ovis. Acute babesiosis occurred in all the lambs infested with adult Rhipicephalus bursa ticks and in one lamb infested with the larvae. The rate of parasitaemia and the degree of anaemia were not correlated. Decrease in the packed-cell volume ranged from 30 to 40%. Parasitized erythrocytes were not observed to block capillaries in the brain, which explained the absence of nervous symptoms in acute babesiosis. The kidneys were the most severely affected organs, exhibiting acute glomerulonephritis. The lesions observed were suggestive of vascular alteration and vascular stasis, leading to anoxia of the tissues. A disseminated intravascular coagulation (DIC) syndrome was recorded in sheep infected with babesiosis. A marked increase in the enzymes of the transaminase groups, mainly aspartate aminotransferase (AST), was observed. Enzymatic changes (increases in AST, alanine aminotransferase (ALT) and lactic dehydrogenase (LDH) and decreases in sorbitol dehydrogenase (SDH), alkaline phosphatase (ALP) and malic enzyme (MEZ)), decreases in total proteins and albumin, and increases in urea and creatinine might reflect the degree of severity of the damage to the liver and kidney tissues. Most of the lambs (85%) that were infested with larvae, and all lambs infested with adult R. bursa ticks, reacted serologically to B. ovis antigen. The serological reactions following infestation with the larvae occurred much later than those following infestation with the adult stage. The lambs which were infested with larvae showed mild clinical reactions when challenged by infected R. bursa adults, as compared with the reactions to the challenge in naive control animals. The serological findings, in addition to the fact that one splenectomized lamb reacted to larval infestation with acute ovine babesiosis, show that the preimaginal stages of R. bursa can transmit B. ovis, usually causing a sub-clinical disease. It is suggested that infections derived from preimaginal ticks in the winter can preimmunize sheep for the subsequent more severe infections derived from adult ticks in the summer. Furthermore, in the absence of a reliable vaccine against B. ovis, grazing flocks in the enzootic regions should be exposed to the preimaginal stages during their activity period (October-February) before exposure to the adult ticks in spring and summer (April-July).

Some epizootiological and clinical aspects of ovine babesiosis caused by Babesia ovis--a review.

The study shows a close relationship between incidence of ovine babesiosis caused by Babesia ovis and the activity period and distribution area of the vector tick Rhipicephalus bursa. The most important factor limiting the distribution of this tick is a decrease in humidity. In general, it is absent from areas with an average annual rainfall of less than about 300 mm. The rate of parasitaemia and the degree of anaemia were not correlated. Decrease of the packed-cell volume ranged from 30 to 40%. Parasitized erythrocytes were not observed to block capillaries in the brain, which explained the absence of nervous symptoms in acute babesiosis. The kidney was the most severely affected organ, exhibiting acute glomerulonephritis. The lesions observed were suggestive of vascular alteration and vascular stasis, leading to anoxia of the tissues. A disseminated intravascular coagulation (DIC) syndrome was recorded in sheep infected with babesiosis. Biochemical studies revealed possible damage to the liver and kidneys. Most of the lambs (85%) that were infested with larvae, and all lambs infested with adult R. bursa ticks reacted serologically to B. ovis antigen. The serological reactions following infestation with the larvae occurred much later than those following infestation with the adult stage. Both transovarial and transstadial transmission of the parasite were demonstrated. A study of antibodies to B. ovis using IFAT in hoggets and ewes revealed high serological prevalence, i.e., 88.9% in ewes and 84.5% in hoggets. No marked seasonal fluctuation was observed. The serological findings, in addition to the fact that one splenectomised lamb reacted to larval infestation with acute ovine babesiosis, show that the preimaginal stages of R. bursa occurring in the winter can transmit B. ovis, usually causing a sub-clinical disease. This might play a major role in pre-immunizing and strengthening the premunition of the sheep against the main spring challenge by the adult ticks. The sub-clinical reactions are probably due to the low infection rate of the preimaginal stages of R. bursa by B. ovis parasites.

Effect of passage of Babesia ovis in the gerbil (Acomys cahirinus) on the course of infection in splenectomized lambs.

Splenectomized gerbils (Acomys cahirinus) have been found to be susceptible to Babesia ovis applied via blood inoculation, whereas intact gerbils were not infected. Blood from splenectomized latently infected gerbils caused infection in a splenectomized lamb. Intact Acomys cahirinus gerbils did not become infected by B. ovis, and all captured rodents in an enzootic area, intact and splenectomized, were found to be negative for B. ovis. It can thus be concluded that Acomys cahirinus does not serve as a natural reservoir for B. ovis.

Sarcoptic mange in wild ruminants in zoological gardens in Israel.

Sarcoptic mange (Sarcoptes scabiei) occurred among wild ruminant species in five zoological gardens in Israel, from 1984 to 1994. Infestation of five ruminants by S. scabiei is reported for the first time: mountain gazelles (Gazella gazella), Nubian ibexes (Capra ibex nubiana), a barbary sheep (Ammotragus lervia), elands (Taurotragus oryx), and an Arabian oryx (Oryx leucoryx). All animals in the herds were administered ivermectin orally at a dose of 200 micrograms/kg body weight daily for 3 consecutive days. This was repeated three times at 2-wk intervals. The disease was eradicated in four small zoos, whereas in the biggest zoo, only control was achieved. Mortality among animals < 4 mo and > 8-yr-old animals composed 65% of mortality among all age classes.

The seasonal occurrence of ticks (Acari: Ixodidae) on sheep and in the field in the Judean area of Israel.

A 2 year survey of ixodid ticks in the Judean area of Israel between 1983 and 1985 showed that sheep were parasitized by the following species: Rhipicephalus sanguineus group (30.6%), Rhipicephalus bursa (25.3%), Haemaphysalis cretica (20.5%), Haemaphysalis otophila (20.1%) and Hyalomma anatolicum excavatum (3.1%). Three other species, Hyalomma marginatum rufipes, Boophilus annulatus and Amblyomma lepidum were also present but in very low numbers. A total of 50,816 specimens (78.1% adult ticks) were collected from the sheep. In the field, a total of 4780 ticks (8.7% adults) were collected and 64.3% consisted of R. bursa. Other species found were H. cretica (14.5%), H. a. excavatum (13.7%), H. otophila (3.4%), R. sanguineus group (1.9%) and 1.7% was Ixodes eldaricus. The number of ticks collected varied from year to year and seasonal activity was observed in all species except for H. a. excavatum. In all species, males outnumbered females, with the exception of H. cretica. The seasonal occurrence, tick ecology and disease relationship is discussed for each species.

A study of an enzootic focus of sheep babesiosis (Babesia ovis, Babes, 1892).

Morbidity and mortality due to Babesia ovis in sheep flocks grazing in an enzootic area of Israel occur yearly, about 2 weeks after detection of adult Rhipicephalus bursa ticks on the animals. Disease incidence peaks in May, but lasts throughout the active period of the adult ticks in the spring-summer months of April-July. No clinical cases of babesiosis have been registered during the active period of the preimaginal stages of R. bursa, from October to February. Incidence of parasitaemia during the spring-summer months was variable, ranging between 2 and 25%. However, in the winter months the incidence of parasitaemia in hoggets increased considerably, reaching 4-60% of the animals. A positive serological response to B. ovis was found in 84.5% of the hoggets and 88.9% of the ewes. In ewes, the prevalence of the serological response showed no marked seasonal variations. Colostral sera of 67.5% and 75% of the ewes and hoggets, respectively, were serologically positive for B. ovis. No antibodies were detected in the sera of lambs less than 3-4 months of age. The epizootiology of sheep babesiosis appears to differ from that of bovine babesiosis.